A comprehensive survey on securing fog computing using blockchain: challenges, protocols, and research directions

The rapid evolution of cloud computing technology has significantly enhanced data processing capabilities, enabling organizations to handle large amounts of data more efficiently. This progress has given rise to new paradigms, such as edge and fog computing, which aim to leverage cloud capabilities more effectively by processing data closer to its source. However, edge/fog computing paradigms inherit many advantages from traditional cloud computing, but they also introduce unique limitations and security challenges that must be addressed. These challenges are mainly caused by the distributed, heterogeneous, and resource-constrained nature of edge/fog environments, which increases risks related to authentication, access control, data integrity, privacy, trust management, and malicious fog nodes. The main objective of this survey is to examine the security issues, constraints, and opportunities associated with integrating Distributed Ledger Technology (DLT) into edge/fog computing. It explores the potential of DLT as a security solution and investigates the practical obstacles that arise during implementation. This survey critically assesses the existing security protocols and solutions implemented in fog computing contexts, aiming to evaluate their effectiveness and identify areas requiring further research and potential future initiatives in edge/fog computing security. Moreover, it encompasses various aspects of edge/fog computing security, including authentication and access control mechanisms, data privacy and confidentiality, trust management, and reputation systems. The findings indicate that DLT can improve decentralised trust, auditability, data integrity, and access control in edge/fog environments, but important limitations remain, including scalability, latency, energy consumption, storage overhead, interoperability, and standardisation. It also addresses security challenges specifically linked to resource-constrained edge devices and presents future challenges in the context of applying DLT within edge/fog computing frameworks. The contribution of this survey is to consolidate recent literature on DLT-enabled edge/fog security, compare existing solutions, identify unresolved limitations, and highlight future research directions for secure and practical blockchain-enabled fog computing systems.